Dimple patterns for golf balls

ABSTRACT

The present invention provides a method for arranging dimples on a golf ball surface that significantly improves aerodynamic symmetry and minimizes parting line visibility by arranging the dimples in a pattern derived from at least one irregular domain generated from a regular or non-regular polyhedron. The method includes choosing control points of a polyhedron, generating an irregular domain based on those control points, packing the irregular domain with dimples, and tessellating the irregular domain to cover the surface of the golf ball. The control points include the center of a polyhedral face, a vertex of the polyhedron, a midpoint or other point on an edge of the polyhedron and others. The method ensures that the symmetry of the underlying polyhedron is preserved while eliminating great circles due to parting lines.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of co-pending U.S. patent applicationSer. No. 13/251,590, filed Oct. 3, 2011, which is a Divisional ofco-pending U.S. patent application Ser. No. 12/262,464 filed Oct. 31,2008, now U.S. Pat. No. 8,029,388, the disclosures of which areincorporated by reference herein in their entirety.

FIELD OF THE INVENTION

This invention relates to golf balls, particularly to golf balls havingimproved dimple patterns. More particularly, the invention relates tomethods of arranging dimples on a golf ball by generating irregulardomains based on polyhedrons, packing the irregular domains withdimples, and tessellating the domains onto the surface of the golf ball.

BACKGROUND OF THE INVENTION

Historically, dimple patterns for golf balls have had a variety ofgeometric shapes, patterns, and configurations. Primarily, patterns arelaid out in order to provide desired performance characteristics basedon the particular ball construction, material attributes, and playercharacteristics influencing the ball's initial launch angle and spinconditions. Therefore, pattern development is a secondary design stepthat is used to achieve the appropriate aerodynamic behavior, therebytailoring ball flight characteristics and performance.

Aerodynamic forces generated by a ball in flight are a result of itsvelocity and spin. These forces can be represented by a lift force and adrag force. Lift force is perpendicular to the direction of flight andis a result of air velocity differences above and below the rotatingball. This phenomenon is attributed to Magnus, who described it in 1853after studying the aerodynamic forces on spinning spheres and cylinders,and is described by Bernoulli's Equation, a simplification of the firstlaw of thermodynamics. Bernoulli's equation relates pressure andvelocity where pressure is inversely proportional to the square ofvelocity. The velocity differential, due to faster moving air on top andslower moving air on the bottom, results in lower air pressure on topand an upward directed force on the ball.

Drag is opposite in sense to the direction of flight and orthogonal tolift. The drag force on a ball is attributed to parasitic drag forces,which consist of pressure drag and viscous or skin friction drag. Asphere is a bluff body, which is an inefficient aerodynamic shape. As aresult, the accelerating flow field around the ball causes a largepressure differential with high-pressure forward and low-pressure behindthe ball. The low pressure area behind the ball is also known as thewake. In order to minimize pressure drag, dimples provide a means toenergize the flow field and delay the separation of flow, or reduce thewake region behind the ball. Skin friction is a viscous effect residingclose to the surface of the ball within the boundary layer.

The industry has seen many efforts to maximize the aerodynamics of golfballs, through dimple disturbance and other methods, though they areclosely controlled by golf's national governing body, the United StatesGolf Association (U.S.G.A.). One U.S.G.A. requirement is that golf ballshave aerodynamic symmetry. Aerodynamic symmetry allows the ball to flywith a very small amount of variation no matter how the golf ball isplaced on the tee or ground. Preferably, dimples cover the maximumsurface area of the golf ball without detrimentally affecting theaerodynamic symmetry of the golf ball.

In attempts to improve aerodynamic symmetry, many dimple patterns arebased on geometric shapes. These may include circles, hexagons,triangles, and the like. Other dimple patterns are based in general onthe five Platonic Solids including icosahedron, dodecahedron,octahedron, cube, or tetrahedron. Yet other dimple patterns are based onthe thirteen Archimedian Solids, such as the small icosidodecahedron,rhomicosidodecahedron, small rhombicuboctahedron, snub cube, snubdodecahedron, or truncated icosahedron. Furthermore, other dimplepatterns are based on hexagonal dipyramids. Because the number ofsymmetric solid plane systems is limited, it is difficult to devise newsymmetric patterns. Moreover, dimple patterns based some of thesegeometric shapes result in less than optimal surface coverage and otherdisadvantageous dimple arrangements. Therefore, dimple properties suchas number, shape, size, and arrangement are often manipulated in anattempt to generate a golf ball that has better aerodynamic properties.

U.S. Pat. No. 5,562,552 to Thurman discloses a golf ball with anicosahedral dimple pattern, wherein each triangular face of theicosahedron is split by a three straight lines which each bisect acorner of the face to form 3 triangular faces for each icosahedral face,wherein the dimples are arranged consistently on the icosahedral faces.

U.S. Pat. No. 5,046,742 to Mackey discloses a golf ball with dimplespacked into a 32-sided polyhedron composed of hexagons and pentagons,wherein the dimple packing is the same in each hexagon and in eachpentagon.

U.S. Pat. No. 4,998,733 to Lee discloses a golf ball formed of ten“spherical” hexagons each split into six equilateral triangles, whereineach triangle is split by a bisecting line extending between a vertex ofthe triangle and the midpoint of the side opposite the vertex, and thebisecting lines are oriented to achieve improved symmetry.

U.S. Pat. No. 6,682,442 to Winfield discloses the use of polygons aspacking elements for dimples to introduce predictable variance into thedimple pattern. The polygons extend from the poles of the ball to aparting line. Any space not filled with dimples from the polygons isfilled with other dimples.

A continuing need exists for a dimple pattern whose dimple arrangementresults in a maximized surface coverage and desirable aerodynamiccharacteristics, including improved symmetry.

SUMMARY OF THE INVENTION

The present invention provides a method for arranging dimples on a golfball surface that significantly improves aerodynamic symmetry andminimizes parting line visibility by arranging the dimples in a patternderived from at least one irregular domain generated from a regular ornon-regular polyhedron. The method includes choosing control points of apolyhedron, generating an irregular domain based on those controlpoints, packing the irregular domain with dimples, and tessellating theirregular domain to cover the surface of the golf ball. The controlpoints include the center of a polyhedral face, a vertex of thepolyhedron, a midpoint or other point on an edge of the polyhedron andothers. The method ensures that the symmetry of the underlyingpolyhedron is preserved while minimizing great circles due to partinglines from the molding process.

The present invention provides methods for generating an irregulardomain based on two or more control points. These methods includeconnecting the control points with a non-linear sketch line, patterningthe sketch line in a first manner to create a first irregular domain,and optionally patterning the sketch line in a second manner to create asecond irregular domain.

The present invention also provides methods for generating one or moreirregular domains based on each set of control points. The center tovertex method, the center to midpoint method, the vertex to midpointmethod, the center to edge method, and the midpoint to center to vertexmethod each provide a single irregular domain that can be tessellated tocover a golf ball. The center to center method, the midpoint to midpointmethod, and the vertex to vertex method each provide two irregulardomains that can be tessellated to cover a golf ball. In each case, theirregular domains cover the surface of the golf ball in a uniformpattern.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which form a part of the specification andare to be read in conjunction therewith and in which like referencenumerals are used to indicate like parts in the various views:

FIG. 1A illustrates a golf ball having dimples arranged by a method ofthe present invention; FIG. 1B illustrates a polyhedron face; FIG. 1Cillustrates an element of the present invention in the polyhedron faceof FIG. 1B; FIG. 1D illustrates a domain formed by a methods of thepresent invention packed with dimples and formed from two elements ofFIG. 1C;

FIG. 2 illustrates a single face of a polyhedron having control pointsthereon;

FIG. 3A illustrates a polyhedron face; FIG. 3B illustrates an element ofthe present invention packed with dimples; FIG. 3C illustrates a domainof the present invention packed with dimples formed from elements ofFIG. 3B; FIG. 3D illustrates a golf ball formed by a method of thepresent invention formed of the domain of FIG. 3C;

FIG. 4A illustrates two polyhedron faces; FIG. 4B illustrates a firstdomain of the present invention in the two polyhedron faces of FIG. 4A;FIG. 4C illustrates a first domain and a second domain of the presentinvention in three polyhedron faces; FIG. 4D illustrates a golf ballformed by a method of the present invention formed of the domains ofFIG. 4C;

FIG. 5A illustrates a polyhedron face; FIG. 5B illustrates a firstdomain of the present invention in a polyhedron face; FIG. 5Cillustrates a first domain and a second domain of the present inventionin three polyhedron faces; FIG. 5D illustrates a golf ball formed usinga method of the present invention formed of the domains of FIG. 5C;

FIG. 6A illustrates a polyhedron face; FIG. 6B illustrates a portion ofa domain of the present invention in the polyhedron face of FIG. 6A;FIG. 6C illustrates a domain formed by the methods of the presentinvention; FIG. 6D illustrates a golf ball formed using the methods ofthe present invention formed of domains of FIG. 6C;

FIG. 7A illustrates a polyhedron face; FIG. 7B illustrates a domain ofthe present invention in the polyhedron face of FIG. 7A; FIG. 7Cillustrates a golf ball formed by a method of the present invention;

FIG. 8A illustrates a first element of the present invention in apolyhedron face; FIG. 8B illustrates a first and a second element of thepresent invention in the polyhedron face of FIG. 8A; FIG. 8C illustratestwo domains of the present invention composed of first and secondelements of FIG. 8B; FIG. 8D illustrates a single domain of the presentinvention based on the two domains of FIG. 8C; FIG. 8E illustrates agolf ball formed using a method of the present invention formed of thedomains of FIG. 8D;

FIG. 9A illustrates a polyhedron face; FIG. 9B illustrates an element ofthe present invention in the polyhedron face of FIG. 9A; FIG. 9Cillustrates two elements of FIG. 9B combining to form a domain of thepresent invention; FIG. 9D illustrates a domain formed by the methods ofthe present invention based on the elements of FIG. 9C; FIG. 9Eillustrates a golf ball formed using a method of the present inventionformed of domains of FIG. 9D;

FIG. 10A illustrates a face of a rhombic dodecahedron; FIG. 10Billustrates a segment of the present invention in the face of FIG. 10A;FIG. 10C illustrates the segment of FIG. 10B and copies thereof forminga domain of the present invention; FIG. 10D illustrates a domain formedby a method of the present invention based on the segments of FIG. 10C;and FIG. 10E illustrates a golf ball formed by a method of the presentinvention formed of domains of FIG. 10D.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment, illustrated in FIG. 1A, the present inventioncomprises a golf ball 10 comprising dimples 12. Dimples 12 are arrangedby packing irregular domains 14 with dimples, as seen best in FIG. 1D.Irregular domains 14 are created in such a way that, when tessellated onthe surface of golf ball 10, they impart greater orders of symmetry tothe surface than prior art balls. The irregular shape of domains 14additionally minimize the appearance and effect of the golf ball partingline from the molding process, and allows greater flexibility inarranging dimples than would be available with regularly shaped domains.

The irregular domains can be defined through the use of any one of theexemplary methods described herein. Each method produces one or moreunique domains based on circumscribing a sphere with the vertices of aregular polyhedron. The vertices of the circumscribed sphere based onthe vertices of the corresponding polyhedron with origin (0,0,0) aredefined below in Table 1.

TABLE 1 Vertices of Circumscribed Sphere based on CorrespondingPolyhedron Vertices Type of Polyhedron Vertices Tetrahedron (+1, +1,+1); (−1, −1, +1); (−1, +1, −1); (+1, −1, −1) Cube (±1, ±1, ±1)Octahedron (±1, 0, 0); (0, ±1, 0); (0, 0, ±1) Dodecahedron (±1, ±1, ±1);(0, ±1/φ, ±φ); (±1/φ, ±φ, 0); (±φ, 0, ±1/φ)* Icosahedron (0, ±1, ±φ);(±1, ±φ, 0); (±φ, 0, ±1)* *φ = (1 + √5)/2

Each method has a unique set of rules which are followed for the domainto be symmetrically patterned on the surface of the golf ball. Eachmethod is defined by the combination of at least two control points.These control points, which are taken from one or more faces of aregular or non-regular polyhedron, consist of at least three differenttypes: the center C of a polyhedron face; a vertex V of a face of aregular polyhedron; and the midpoint M of an edge of a face of thepolyhedron. FIG. 2 shows an exemplary face 16 of a polyhedron (a regulardodecahedron in this case) and one of each a center C, a midpoint M, avertex V, and an edge E on face 16. The two control points C, M, or Vmay be of the same or different types. Accordingly, six types of methodsfor use with regular polyhedrons are defined as follows:

1. Center to midpoint (C→M);

2. Center to center (C→C);

3. Center to vertex (C→V);

4. Midpoint to midpoint (M→M);

5. Midpoint to Vertex (M→V); and

6. Vertex to Vertex (V→V).

While each method differs in its particulars, they all follow the samebasic scheme. First, a non-linear sketch line is drawn connecting thetwo control points. This sketch line may have any shape, including, butnot limited, to an arc, a spline, two or more straight or arcuate linesor curves, or a combination thereof. Second, the sketch line ispatterned in a method specific manner to create a domain, as discussedbelow. Third, when necessary, the sketch line is patterned in a secondfashion to create a second domain.

While the basic scheme is consistent for each of the six methods, eachmethod preferably follows different steps in order to generate thedomains from a sketch line between the two control points, as describedbelow with reference to each of the methods individually.

The Center to Vertex Method

Referring again to FIGS. 1A-1D, the center to vertex method yields onedomain that tessellates to cover the surface of golf ball 10. The domainis defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 1A-1D use an        icosahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 1B;    -   3. Center C of face 16, and a first vertex V₁ of face 16 are        connected with any non-linear sketch line, hereinafter referred        to as a segment 18;    -   4. A copy 20 of segment 18 is rotated about center C, such that        copy 20 connects center C with vertex V₂ adjacent to vertex V₁.        The two segments 18 and 20 and the edge E connecting vertices V₁        and V₂ define an element 22, as shown best in FIG. 1C; and    -   5. Element 22 is rotated about midpoint M of edge E to create a        domain 14, as shown best in FIG. 1D.

When domain 14 is tessellated to cover the surface of golf ball 10, asshown in FIG. 1A, a different number of total domains 14 will resultdepending on the regular polyhedron chosen as the basis for controlpoints C and V₁. The number of domains 14 used to cover the surface ofgolf ball 10 is equal to the number of faces P_(F) of the polyhedronchosen times the number of edges P_(E) per face of the polyhedrondivided by 2, as shown below in Table 2.

Domains Resulting from Use of Specific Polyhedra When Using the Centerto Vertex Method

Number Type of of Faces, Number of Edges, Number of Domains PolyhedronP_(F) P_(E) 14 Tetrahedron 4 3 6 Cube 6 4 12 Octahedron 8 3 12Dodecahedron 12 5 30 Icosahedron 20 3 30

The Center to Midpoint Method

Referring to FIGS. 3A-3D, the center to midpoint method yields a singleirregular domain that can be tessellated to cover the surface of golfball 10. The domain is defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 3A-3D use a        dodecahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 3A;    -   3. Center C of face 16, and midpoint M₁ of a first edge E₁ of        face 16 are connected with a segment 18;    -   4. A copy 20 of segment 18 is rotated about center C, such that        copy 20 connects center C with a midpoint M₂ of a second edge E₂        adjacent to first edge E₁. The two segments 16 and 18 and the        portions of edge E₁ and edge E₂ between midpoints M₁ and M₂        define an element 22; and    -   5. Element 22 is patterned about vertex V of face 16 which is        contained in element 22 and connects edges E₁ and E₂ to create a        domain 14.

When domain 14 is tessellated around a golf ball 10 to cover the surfaceof golf ball 10, as shown in FIG. 3D, a different number of totaldomains 14 will result depending on the regular polyhedron chosen as thebasis for control points C and M₁. The number of domains 14 used tocover the surface of golf ball 10 is equal to the number of verticesP_(V) of the chosen polyhedron, as shown below in Table 3.

TABLE 3 Domains Resulting From Use of Specific Polyhedra When Using theCenter to Midpoint Method Type of Polyhedron Number of Vertices, P_(V)Number of Domains 14 Tetrahedron 4 4 Cube 8 8 Octahedron 6 6Dodecahedron 20 20 Icosahedron 12 12

The Center to Center Method

Referring to FIGS. 4A-4D, the center to center method yields two domainsthat can be tessellated to cover the surface of golf ball 10. Thedomains are defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 4A-4D use a        dodecahedron);    -   2. Two adjacent faces 16 a and 16 b of the regular polyhedron        are chosen, as shown in FIG. 4A;    -   3. Center C₁ of face 16 a, and center C₂ of face 16 b are        connected with a segment 18;    -   4. A copy 20 of segment 18 is rotated 180 degrees about the        midpoint M between centers C₁ and C₂, such that copy 20 also        connects center C₁ with center C₂, as shown in FIG. 4B. The two        segments 16 and 18 define a first domain 14 a; and    -   5. Segment 18 is rotated equally about vertex V to define a        second domain 14 b, as shown in FIG. 4C.

When first domain 14 a and second domain 14 b are tessellated to coverthe surface of golf ball 10, as shown in FIG. 4D, a different number oftotal domains 14 a and 14 b will result depending on the regularpolyhedron chosen as the basis for control points C₁ and C₂. The numberof first and second domains 14 a and 14 b used to cover the surface ofgolf ball 10 is P_(F)*P_(E)/2 for first domain 14 a and P_(V) for seconddomain 14 b, as shown below in Table 4.

TABLE 4 Domains Resulting From Use of Specific Polyhedra When Using theCenter to Center Method Number of Number Number of Number of FirstNumber of Second Type of Vertices, Domains of Faces, Edges, DomainsPolyhedron P_(V) 14a P_(F) P_(E) 14b Tetrahedron 4 6 4 3 4 Cube 8 12 6 48 Octahedron 6 9 8 3 6 Dodecahedron 20 30 12 5 20 Icosahedron 12 18 20 312

The Midpoint to Midpoint Method

Referring to FIGS. 5A-5D, the midpoint to midpoint method yields twodomains that tessellate to cover the surface of golf ball 10. Thedomains are defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 5A-5D use a        dodecahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 5A;    -   3. The midpoint M₁ of a first edge E₁ of face 16, and the        midpoint M₂ of a second edge E₂ adjacent to first edge E₁ are        connected with a segment 18;    -   4. Segment 18 is patterned around center C of face 16 to form a        first domain 14 a, as shown in FIG. 5B;    -   5. Segment 18, along with the portions of first edge E₁ and        second edge E₂ between midpoints M₁ and M₂, define an element        22; and    -   6. Element 22 is patterned about vertex V which is contained in        element 22 and connects edges E₁ and E₂ to create a second        domain 14 b, as shown in FIG. 5C.

When first domain 14 a and second domain 14 b are tessellated to coverthe surface of golf ball 10, as shown in FIG. 5D, a different number oftotal domains 14 a and 14 b will result depending on the regularpolyhedron chosen as the basis for control points M₁ and M₂. The numberof first and second domains 14 a and 14 b used to cover the surface ofgolf ball 10 is P_(F) for first domain 14 a and P_(V) for second domain14 b, as shown below in Table 5.

TABLE 5 Domains Resulting From Use of Specific Polyhedra When Using theCenter to Center Method Number of Number of Second Type of Number ofNumber of First Vertices, Domains Polyhedron Faces, P_(F) Domains 14aP_(V) 14b Tetrahedron 4 4 4 4 Cube 6 6 8 8 Octahedron 8 8 6 6Dodecahedron 12 12 20 20 Icosahedron 20 20 12 12

The Midpoint to Vertex Method

Referring to FIGS. 6A-6D, the midpoint to vertex method yields onedomain that tessellates to cover the surface of golf ball 10. The domainis defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 6A-6D use a        dodecahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 6A;    -   3. A midpoint M₁ of edge E₁ of face 16 and a vertex V₁ on edge        E₁ are connected with a segment 18;    -   4. Copies 20 of segment 18 is patterned about center C of face        16, one for each midpoint M₂ and vertex V₂ of face 16, to define        a portion of domain 14, as shown in FIG. 6B; and    -   5. Segment 18 and copies 20 are then each rotated 180 degrees        about their respective midpoints to complete domain 14, as shown        in FIG. 6C.

When domain 14 is tessellated to cover the surface of golf ball 10, asshown in FIG. 6D, a different number of total domains 14 will resultdepending on the regular polyhedron chosen as the basis for controlpoints M₁ and V₁. The number of domains 14 used to cover the surface ofgolf ball 10 is P_(F), as shown in Table 6.

TABLE 6 Domains Resulting From Use of Specific Polyhedra When Using theMidpoint to Vertex Method Type of Polyhedron Number of Faces, P_(F)Number of Domains 14 Tetrahedron 4 4 Cube 6 6 Octahedron 8 8Dodecahedron 12 12 Icosahedron 20 20

The Vertex to Vertex Method

Referring to FIGS. 7A-7C, the vertex to vertex method yields two domainsthat tessellate to cover the surface of golf ball 10. The domains aredefined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 7A-7C use an        icosahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 7A;    -   3. A first vertex V₁ face 16, and a second vertex V₂ adjacent to        first vertex V₁ are connected with a segment 18;    -   4. Segment 18 is patterned around center C of face 16 to form a        first domain 14 a, as shown in FIG. 7B;    -   5. Segment 18, along with edge E₁ between vertices V₁ and V₂,        defines an element 22; and    -   6. Element 22 is rotated around midpoint M₁ of edge E₁ to create        a second domain 14 b.

When first domain 14 a and second domain 14 b are tessellated to coverthe surface of golf ball 10, as shown in FIG. 7C, a different number oftotal domains 14 a and 14 b will result depending on the regularpolyhedron chosen as the basis for control points V₁ and V₂. The numberof first and second domains 14 a and 14 b used to cover the surface ofgolf ball 10 is P_(F) for first domain 14 a and P_(F)*P_(E)/2 for seconddomain 14 b, as shown below in Table 7.

TABLE 7 Domains Resulting From Use of Specific Polyhedra When Using theVertex to Vertex Method Number of Number Number of Second Type of Numberof of First Edges per Face, Domains Polyhedron Faces, P_(F) Domains 14aP_(E) 14b Tetrahedron 4 4 3 6 Cube 6 6 4 12 Octahedron 8 8 3 12Dodecahedron 12 12 5 30 Icosahedron 20 20 3 30

While the six methods previously described each make use of two controlpoints, it is possible to create irregular domains based on more thantwo control points. For example, three, or even more, control points maybe used. The use of additional control points allows for potentiallydifferent shapes for irregular domains. An exemplary method using amidpoint M, a center C and a vertex V as three control points forcreating one irregular domain is described below.

The Midpoint to Center to Vertex Method

Referring to FIGS. 8A-8E, the midpoint to center to vertex method yieldsone domain that tessellates to cover the surface of golf ball 10. Thedomain is defined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 8A-8E use an        icosahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 8A;    -   3. A midpoint M₁ on edge E₁ of face 16, Center C of face 16 and        a vertex V₁ on edge E₁ are connected with a segment 18, and        segment 18 and the portion of edge E₁ between midpoint M₁ and        vertex V₁ define a first element 22 a, as shown in FIG. 8A;    -   4. A copy 20 of segment 18 is rotated about center C, such that        copy 20 connects center C with a midpoint M₂ on edge E₂ adjacent        to edge E₁, and connects center C with a vertex V₂ at the        intersection of edges E₁ and E₂, and the portion of segment 18        between midpoint M₁ and center C, the portion of copy 20 between        vertex V₂ and center C, and the portion of edge E₁ between        midpoint M₁ and vertex V₂ define a second element 22 b, as shown        in FIG. 8B; 5. First element 22 a and second element 22 b are        rotated about midpoint M₁ of edge E₁, as seen in FIGS. 8C, to        define two domains 14, wherein a single domain 14 is bounded        solely by portions of segment 18 and copy 20 and the rotation        18′ of segment 18, as seen in FIG. 8D. When domain 14 is        tessellated to cover the surface of golf ball 10, as shown in        FIG. 8E, a different number of total domains 14 will result        depending on the regular polyhedron chosen as the basis for        control points M, C, and V. The number of domains 14 used to        cover the surface of golf ball 10 is equal to the number of        faces P_(F) of the polyhedron chosen times the number of edges        P_(E) per face of the polyhedron, as shown below in Table 8.

TABLE 8 Domains Resulting From Use of Specific Polyhedra When Using theMidpoint to Center to Vertex Method Type of Number of Number of Edges,Number of Domains Polyhedron Faces, P_(F) P_(E) 14 Tetrahedron 4 3 12Cube 6 4 24 Octahedron 8 3 24 Dodecahedron 12 5 60 Icosahedron 20 3 60

While the methods described previously provide a framework for the useof center C, vertex V, and midpoint M as the only control points, othercontrol points are usable. For example, a control point may be any pointP on an edge E of the chosen polyhedron face. When this type of controlpoint is used, additional types of domains may be generated, though themechanism for creating the irregular domain(s) may be different. Anexemplary method, using a center C and a point P on an edge, forcreating one such irregular domain is described below.

The Center to Edge Method

Referring to FIGS. 9A-9E, the center to edge method yields one domainthat tessellates to cover the surface of golf ball 10. The domain isdefined as follows:

-   -   1. A regular polyhedron is chosen (FIGS. 9A-9E use an        icosahedron);    -   2. A single face 16 of the regular polyhedron is chosen, as        shown in FIG. 9A;    -   3. Center C of face 16, and a point P₁ on edge E₁ are connected        with a segment 18,    -   4. A copy 20 of segment 18 is rotated about center C, such that        copy 20 connects center C with a point P₂ on edge E₂ adjacent to        edge E₁, where point P₂ is positioned identically relative to        edge E₂ as point P₁ is positioned relative to edge E₁, such that        the two segments 18 and 20 and the portions of edges E₁ and E₂        between points P₁ and P₂, respectively, and a vertex V, which        connects edges E₁ and E₂, define an element 22, as shown best in        FIG. 9B; and    -   5. Element 22 is rotated about midpoint M₁ of edge E₁ or        midpoint M₂ of edge E₂, whichever is located within element 22,        as seen in FIGS. 9B-9C, to create a domain 14, as seen in FIG.        9D.

When domain 14 is tessellated to cover the surface of golf ball 10, asshown in FIG. 9E, a different number of total domains 14 will resultdepending on the regular polyhedron chosen as the basis for controlpoints C and P₁. The number of domains 14 used to cover the surface ofgolf ball 10 is equal to the number of faces P_(F) of the polyhedronchosen times the number of edges P_(E) per face of the polyhedrondivided by 2, as shown below in Table 9.

TABLE 9 Domains Resulting From Use of Specific Polyhedra When Using theCenter to Edge Method Type of Number of Number of Edges, Number ofDomains Polyhedron Faces, P_(F) P_(E) 14 Tetrahedron 4 3 6 Cube 6 4 12Octahedron 8 3 12 Dodecahedron 12 5 30 Icosahedron 20 3 30

Though each of the above described methods has been explained withreference to regular polyhedrons, they may also be used with certainnon-regular polyhedrons, such as Archimedean Solids, Catalan Solids, orothers. The methods used to derive the irregular domains will generallyrequire some modification in order to account for the non-regular faceshapes of the non-regular solids. An exemplary method for use with aCatalan Solid, specifically a rhombic dodecahedron, is described below.

A Vertex to Vertex Method for a Rhombic Dodecahedron

Referring to FIGS. 10A-10E, a vertex to vertex method based on a rhombicdodecahedron yields one domain that tessellates to cover the surface ofgolf ball 10. The domain is defined as follows:

-   -   1. A single face 16 of the rhombic dodecahedron is chosen, as        shown in FIG. 10A;    -   2. A first vertex V₁ face 16, and a second vertex V₂ adjacent to        first vertex V₁ are connected with a segment 18, as shown in        FIG. 10B;    -   3. A first copy 20 of segment 18 is rotated about vertex V₂,        such that it connects vertex V₂ to vertex V3 of face 16, a        second copy 24 of segment 18 is rotated about center C, such        that it connects vertex V₃ and vertex V₄ of face 16, and a third        copy 26 of segment 18 is rotated about vertex V₁ such that it        connects vertex V₁ to vertex V₄, all as shown in FIG. 10C, to        form a domain 14, as shown in FIG. 10D;

When domain 14 is tessellated to cover the surface of golf ball 10, asshown in FIG. 10E, twelve domains will be used to cover the surface ofgolf ball 10, one for each face of the rhombic dodecahedron.

After the irregular domain(s) is created using any of the above methods,the domain(s) may be packed with dimples in order to be usable increating golf ball 10. There are no limitations on how the dimples arepacked. There are likewise no limitations to the dimple shapes orprofiles selected to pack the domains. Though the present inventionincludes substantially circular dimples in one embodiment, dimples orprotrusions (brambles) having any desired characteristics and/orproperties may be used. For example, in one embodiment the dimples mayhave a variety of shapes and sizes including different depths andwidths. In particular, the dimples may be concave hemispheres, or theymay be triangular, square, hexagonal, catenary, polygonal or any othershape known to those skilled in the art. They may also have straight,curved, or sloped edges or sides. To summarize, any type of dimple orprotrusion (bramble) known to those skilled in the art may be used withthe present invention. The dimples may all fit within each domain, asseen in FIGS. 1A and 1D, or dimples may be shared between one or moredomains, as seen in FIGS. 3C-3D, so long as the dimple arrangement oneach independent domain remains consistent across all copies of thatdomain on the surface of a particular golf ball. Alternatively, thetessellation can create a pattern that covers more than about 60%,preferably more than about 70% and preferably more than about 80% of thegolf ball surface without using dimples.

In other embodiments, the domains may not be packed with dimples, andthe borders of the irregular domains may instead comprise ridges orchannels. In golf balls having this type of irregular domain, the one ormore domains or sets of domains preferably overlap to increase surfacecoverage of the channels. Alternatively, the borders of the irregulardomains may comprise ridges or channels and the domains are packed withdimples.

When the domain(s) is patterned onto the surface of a golf ball, thearrangement of the domains dictated by their shape and the underlyingpolyhedron ensures that the resulting golf ball has a high order ofsymmetry, equaling or exceeding 12. The order of symmetry of a golf ballproduced using the method of the current invention will depend on theregular or non-regular polygon on which the irregular domain is based.The order and type of symmetry for golf balls produced based on the fiveregular polyhedra are listed below in Table 10.

TABLE 10 Symmetry of Golf Ball of the Present Invention as a Function ofPolyhedron Type of Polyhedron Type of Symmetry Symmetrical OrderTetrahedron Chiral Tetrahedral Symmetry 12 Cube Chiral OctahedralSymmetry 24 Octahedron Chiral Octahedral Symmetry 24 Dodecahedron ChiralIcosahedral Symmetry 60 Icosahedron Chiral Icosahedral Symmetry 60

These high orders of symmetry have several benefits, including more evendimple distribution, the potential for higher packing efficiency, andimproved means to mask the ball parting line. Further, dimple patternsgenerated in this manner may have improved flight stability and symmetryas a result of the higher degrees of symmetry.

In other embodiments, the irregular domains do not completely cover thesurface of the ball, and there are open spaces between domains that mayor may not be filled with dimples. This allows dissymmetry to beincorporated into the ball.

While the preferred embodiments of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not of limitation. It will be apparent topersons skilled in the relevant art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the invention. For example, while the preferred polyhedral shapeshave been provided above, other polyhedral shapes could also be used.Thus the present invention should not be limited by the above-describedexemplary embodiments, but should be defined only in accordance with thefollowing claims and their equivalents.

We claim:
 1. A golf ball having dimples based on a polyhedron pattern,wherein the dimples are arranged in irregular domains comprised ofnon-linear segments, wherein the irregular domains are tessellated overa surface of the golf ball and are defined by a non-linear line from afirst vertex of a face of the polyhedron to a second vertex.